Three-dimensional numerical simulation of impedance hole rounding on surge chamber

The impedance hole rounding on surge chamber is numerically simulated by using the k-e turbulence mathematical model for the complementation of physical model tests.The inflow and outflow resistance coefficients at the junction rounding with different radii of the impedance hole with the bottom plate of surge chamber and the bottom flow conduits are obtained.The calculated flow pattern of surge chamber without impedance hole rounding is compared with the observed one.The results show that when the flows without impedance hole rounding go through the hole,a sudden flow contraction occurs,the flow velocity is uneven,faster in the middle but slower at the sides,and the resistance coefficient is relatively large.After the impedance hole rounding,the sudden contraction effect is significantly reduced,the flows are smooth and even,and the resistance coefficient obviously decreases.The impedance hole rounding optimizes and reduces the contraction losses and may effectively reduce the resistance coefficient so as to raise the discharge coefficient of the impedance hole.